The Lieutenant Tang (Acanthurus tennenti), also known as Tennent’s surgeonfish or doubleband surgeonfish, is a species of marine ray-finned fish belonging to the family Acanthuridae. It is found in the Indian Ocean and is popular in the marine aquarium trade.

Physical Description

The Lieutenant Tang has an oval-shaped, laterally compressed body. The overall coloration is olive-brown to grey with two distinctive black bands or ‘lieutenant stripes’ running vertically down the body, which give this species its common name. The dorsal fin has 9 spines and 24-27 soft rays while the anal fin has 3 spines and 22-24 soft rays. This species reaches a maximum total length of 25 cm (9.8 in).

Distribution and Habitat

The Lieutenant Tang is found in the Indian Ocean from Sri Lanka and the Maldives to Indonesia and western Thailand. It inhabits shallow coral reefs and lagoons at depths between 2 and 30 meters.

Diet and Feeding

The Lieutenant Tang is herbivorous, grazing on benthic algae and filamentous algae. In captivity, it should be offered a varied diet including marine algae, spirulina, and high-quality vegetable-based preparations.

Aquarium Care

The Lieutenant Tang requires a well-established aquarium of at least 125 gallons with abundant live rock for grazing. It is semi-aggressive and may display territorial behavior toward other tangs. Generally considered reef-safe.

Conservation Status

Classified as Least Concern by the IUCN Red List.